JPS5816069Y2 - chikusekigatakanchiki - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a storage type sensor that operates when a phenomenon to be detected continues for a certain period of time or more.

Among general sensors that operate by detecting a certain physical phenomenon such as light or smoke, there is a so-called accumulation type sensor that operates when the phenomenon continues for a certain period of time or more.

To explain this using a smoke detector as an example, an accumulation type smoke detector operates only when smoke of a certain concentration or higher is detected for a certain period of time.

FIG. 1 shows an example of this type of ionization type smoke detector, in which the inner chamber 2 of the detection section 1 is sealed, and the outer chamber 3 is open to allow smoke to flow into it.

The air inside the inner chamber 2 and the outer chamber 3 is ionized by α rays emitted by isotopes such as Am241, and a small ion current flows.

r2. r3. r4 is a reference voltage setting resistor input to the input terminal t1 of the comparator 5, and is set to the reference voltage vZ.

Now, if smoke flows into the external chamber 3 due to a fire or the like, the ion current flowing in the external chamber becomes difficult to flow, and the voltage drop in the chamber becomes large.

Therefore, the voltage 68 between the gate and source of the FET becomes large, and the drain current ID flowing from the drain to the source increases.
S increases, the voltage applied to the resistor r1 increases, and this is input to the input terminal t2 of the comparator 5 as the input voltage V+.

The comparator 5 compares the above-mentioned set voltage 7 with this input voltage V+, and operates when Vz<V+, and outputs a current 2 from the output terminal t3.

output. Current■. is the resistance r5. r6, the capacitor C1 is charged with a time constant determined by the value of the capacitor C1, and the potential of the anode A of the PUT (programmable unijunction transistor) P is raised.

On the other hand, a constant potential determined by a resistor r8°r is applied to the gate G.

Therefore, if smoke flows into the external chamber 3 at a voltage higher than a certain level, F
ET continues to be on, which causes comparator 5 to draw current ■.

As it continues to output, the charged potential of the capacitor C1 (anode A potential) gradually rises, and when it becomes higher than the potential of the gate G, PUTP becomes conductive and the charged charge of the capacitor C1 is discharged, and this is connected to the cathode K. Thyristor S
Flows into the gate of CR as a trigger current and connects the thyristor SC.
Turn on R.

Relay L is energized by turning on thyristor SCR, and activates an alarm or the like controlled by relay L.

On the other hand, for a certain period of time (the charging potential of capacitor C1 is
When the inflow of smoke stops and the FET turns off within the charging time until the potential becomes higher than the gate G potential of P, the comparator 5 also turns off, and the charge that had been charged in the capacitor C1 is transferred to the diode D and the resistor r5. , is discharged through the comparator 5 with a time constant smaller than the charging time constant, and the sensor does not operate.

Compared to ordinary smoke detectors, this storage type smoke detector is more susceptible to malfunctions caused by causes other than fire, such as wind, cigarette smoke, insect intrusion, static electricity, and external electrical noise. Very few alarms can be issued with high reliability.

However, the reference voltage resistor r2. r3. The power consumed by r4 and the power consumed by the comparator 5 cannot be ignored, and the structure is relatively complicated, resulting in high cost.

In order to eliminate the above-mentioned drawbacks, the present invention attempts to provide a storage type sensor that is inexpensive and consumes less power by using a complementary MO5 (complementary MO5) IC called C-MOS.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows an embodiment of the ionization type smoke detector of the present invention.

In the figure, reference numeral 1 denotes an ionization type smoke detection section, which is composed of an internal ionization chamber 2 having an internal electrode 2A, an external ionization chamber 3 having an external electrode 3A, and an intermediate electrode 4.

The air in the internal ionization chamber 2 and the external ionization chamber 3 is Arn241.
It is ionized by alpha rays of isotopes such as

The internal and external ionization chambers 2 and 3 are connected in series to a power source E, and therefore a small ionization current is constantly flowing.

6 is a C-MOS, P-channel MO8FET (hereinafter referred to as P-
Ql (referred to as MO3) and N-channel MO3FET (referred to as N
- MO8) consists of Q2.

Output terminal t1 is connected to output terminal t2 via variable resistor r1□.
are connected to the connection point between the anode A of PUTP and the capacitor C1 via a variable resistor rlO.

The input terminal t4 is connected to the intermediate electrode 4 of the detection section 1.

t3. t5 is a power supply terminal.

PUTP game) G is the resistance r8. r9 is connected to the series connection point of the resistor r8. A voltage determined by the resistance ratio of r9 is applied as the potential of G).

SCR is a thyristor for energizing relay L, and its gate is connected to the cathode of PUTP, the series connection point of resistor r7, and capacitor C2.

PUTP and thyristor SCR constitute a switching circuit of relay L.

Next, the operation of this circuit will be explained.

Under normal conditions, the voltage of the intermediate electrode 4 is maintained at a certain constant voltage.

At this constant voltage, P-MO5Ql is off, N-MO8Q
2 is set in advance to be in the on state.

If smoke flows into the external ionization chamber 3 due to a fire or the like in such a state, the ion current decreases and the potential of the intermediate electrode 4 drops, turning P-MO3Q1 on and N-MO8Q2 off.

Therefore, a current flows in the circuit of L3QI Lr1o C1, and charging of the capacitor C1 is started with a time constant determined by the resistor rto and the capacitor C1.

The potential of the anode A of PUTP gradually increases as the capacitor C1 is charged, and the potential of the anode A of PUTP increases to a value determined by the ratio of resistors r8 and r9.
When the potential is greater than -G potential, PUTP becomes conductive.

The charge on capacitor C1 is discharged through PUTP,
A part of it flows as a trigger current to the gate of the thyristor SCR, making the thyristor SCR conductive.

As a result, a current flows through the E(+)-L-3CR-E(-) circuit, energizing the relay L, and operating an alarm device, etc., which is not shown, controlled by the contacts of the relay L.

On the other hand, when the inflow of smoke into the external ionization chamber 3 stops within a certain period of time, the potential of the intermediate electrode 4 returns to the normal constant potential P-M
O8Q, is switched off and N-MO5Q2 is switched on again.

Therefore, the charge that had been stored in the capacitor C1 to some extent is discharged in the circuit of C1r1□-tl-Q2jscx,
This storage type sensor remains inactive.

In this invention, during normal monitoring, C-MOS is used as described above.
Since P-MO3Q1 of No. 6 is in the off state, its impedance becomes a high value of approximately several thousand M, Q, and almost no current flows, allowing many sensors to be connected in parallel to the same alarm line. .

Also, by adjusting the variable resistor 10, the charging time of the capacitor C can be adjusted, so when smoke continues to flow into the detection part 1, the circuit is activated and the relay L is energized. You can easily adjust that time.

On the other hand, by adjusting the variable resistor r1□, the discharge time of the capacitor C can be adjusted.

In other words, the operating time and reset time of the sensor can be freely set by adjusting the variable resistors rlo and rll.

Therefore, if the sensor is installed in a place where there is a cause other than a fire that often lowers the potential of the intermediate electrode 4 for a short period of time, the operating time can be increased by increasing the variable resistor rlo and decreasing the variable resistor r1□. Therefore, most malfunctions can be prevented.

Fig. 3 is a circuit diagram showing an embodiment of the present invention in a photoelectric smoke detector, except that the ionization type smoke detection part in Fig. 2 is replaced with a rechargeable smoke detection part, and the other parts are the same, so they are the same. Circuit parts are shown with the same symbols.

In the figure, LED is a light emitting diode, Cd51°Cd5
2 is a photoconductive element, and 7 is a shielding plate.

To explain this operation, the light emitting diode LED normally connected to the power source E emits light, but the light is blocked by the shielding plate 7 and is not input to the photoconductive element Cd52, which is a light receiving element.

Therefore, photoconductive element Cd51. A constant voltage determined by the internal resistance ratio of Cds is applied to the input terminal t4.

At this constant voltage, PMO8Q turns off, N-MO8Q
2 is set to on.

If smoke flows into the detection unit 1 due to a fire or the like, the light from the light emitting diode LED will be scattered by the smoke particles, and a part of the scattered light will enter the photoconductive element Cd52, and the resistance value of the photoconductive element Cd52 will be decrease.

As a result, the input voltage at the input terminal t4 decreases, and P-MO3
Q is turned on and N-MO5Q2 is turned off.

Hereafter, it operates in the same way as the ionization type smoke detector shown in Figure 2,
Relay L is energized and a fire alarm is issued.

Photoconductive element Cd51. If Cd52 is replaced with a thermally responsive element such as a thermistor or a positor, and one of the elements is made sensitive to changes in heat while the other is made insensitive, it can be used as a thermal fire detector that is activated by a sudden rise in heat. be able to.

As explained in detail above, by providing a complementary MO8IC and a variable resistor, the storage type sensor of the present invention has a small number of parts, is small and lightweight, and is low in cost, as is clear when comparing the conventional device shown in Fig. 1. A sensor with low power consumption can be provided.

Furthermore, it is possible to easily adjust the storage (operation) time and the recovery time independently, allowing the sensor to be optimally suited to the conditions of the installation location, resulting in extremely low malfunctions and, therefore, high reliability. It has various advantages such as high

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional storage type smoke detector, and FIG. 2 is a circuit diagram showing an embodiment of the storage type ionization type smoke detector of the present invention.
FIG. 3 is a circuit diagram showing another embodiment of the present invention. In the figure, 1 is the detection section, 6 is the complementary MO8IC1rl
o is a charging resistor, r1□ is a discharging resistor, C1 is a capacitor, and P and SCR are switching circuits.

Claims (1)

[Scope of utility model registration request] a detection section that detects a specific physical phenomenon; a complementary MO3IC that is actuated by the detection output from the detection section to invert the output states of two output terminals; A charging resistor with a large resistance value, one end of which is connected to a first output terminal that is turned on when the threshold is exceeded, and a second output that is turned on when the output of the detection section is below the threshold. A discharging resistor with a small resistance value is connected at one end to a terminal, a capacitor is commonly connected to the other end of both of these resistors for charging and discharging, and the capacitor operates when the capacitor is charged to a certain voltage or higher. A storage type sensor comprising a switching circuit.